Marine geophysical equipment cleaner

ABSTRACT

Techniques are disclosed relating to an apparatus with scraping members for cleaning a geophysical equipment (e.g., a streamer) being towed behind a survey vessel. The apparatus may, in one embodiment, include a housing and a plurality of scraping members that are disposed at least partially outside of the housing. In another embodiment, when the geophysical equipment is being towed behind a survey vessel, portions of the geophysical equipment may be flattened or compressed due to the towing force exerted on the geophysical equipment, and the apparatus of this disclosure may still be used to clean the geophysical equipment. A method is disclosed related to operating an apparatus with a plurality of scraping members and removing debris from a geophysical equipment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.14/068,834, filed Oct. 31, 2013 (now U.S. Pat. No. 9,488,753), whichclaims priority to U.S. Provisional Appl. No. 61/824,218 filed May 16,2013; the disclosures of each of the above-referenced applications areincorporated by reference herein in their entireties.

BACKGROUND

This application generally relates to the field of marine geophysicalprospecting. More specifically, the application relates to equipment andmethods for geophysical prospecting. In particular, anti-debrisequipment and methods are disclosed.

In the oil and gas exploration industry, marine geophysical prospectingis commonly used in the search for subterranean formations. Marinegeophysical prospecting techniques yield knowledge of the subsurfacestructure of the Earth, which is useful for finding and extractinghydrocarbon deposits such as oil and natural gas. Seismic surveying andelectromagnetic surveying are two of the well-known techniques of marinegeophysical prospecting.

For example, in a seismic survey conducted in a marine environment(which may include saltwater, freshwater, and/or brackish waterenvironments), one or more seismic energy sources are typicallyconfigured to be submerged and towed by a survey vessel. The surveyvessel is typically also configured to tow one or more (typically aplurality of) laterally-spaced streamers through the water.Electromagnetic surveys may tow equipment, including streamers, in asimilar fashion. Some techniques of geophysical prospecting involve thesimultaneous use of seismic and electromagnetic survey equipment.

In a typical marine survey, the streamers on which the sensors arelocated are very long, typically multiple kilometers in length. Somesurveys may be conducted with a single streamer, while some surveysutilize multiple streamer systems including one or more arrays ofstreamers. The exterior of towed equipment, such as streamers andrelated equipment, are subject to accumulation of debris (e.g., seaweed,marine organisms, barnacles, or algae). Such accumulations can increasedrag on the equipment as it is towed through the water, making towingmore difficult and expensive, and subjecting the equipment tomalfunction or damage, as well as causing turbulence that may increasetowing noise and degrade the quality of recorded signals.

Scrapers may be employed to remove debris from the exterior of marinesurvey equipment, such as streamers. A common type of scrapers is ametal scraper (e.g., barnacle scraper) that may be clamped around astreamer. Some scrapers may have a tendency to slide over the debriswithout removing it. Some scrapers may also have a tendency to beclogged by debris. As a result, the cleaning operation may need to besuspended to unclog the scraper. Inefficiency in the cleaning operationtypically increases survey downtime and survey cost. Such cleaningoperation can be difficult to perform, dangerous to personnel in theevent of unexpected rough water, and, depending on the skill of thecleaning operator, may risk damage to the streamer.

Geophysical equipment including some streamers known in the art mayinclude sensors, streamer positioning devices, birds, connectors, andvarious other devices along their lengths. Geophysical equipment mayinclude, for example, streamer positioning devices (e.g., lateral forceand depth control devices known as “birds”) and sensors for acousticdetection. Moreover, streamers known in the art may have sections alongtheir length with different diameters (either by design or as a resultof towing effects). There exists a need for a marine geophysicalequipment cleaning device that can traverse an entire deployed streamer,wherein the streamer has a varying diameter along the length, and/or thestreamer includes such components as sensors, streamer positioningdevices, birds, connectors, and other devices.

While at least a portion of the explanation of the need provided hereinrefers to seismic surveying, it is important to recognize that thesurvey system here is not limited to seismic survey but rather anysurvey system which includes a cable towed by a vessel including asurvey vessel. Such other types of cables may include, withoutlimitation, electrodes, magnetometers and temperature sensors.Accordingly, the references to seismic streamers are provided asnon-limiting examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a survey vessel towing an array of streamers in a body ofwater with an apparatus attached around one of the streamers.

FIG. 2A depicts an embodiment of an apparatus attached to and around anexterior of a streamer.

FIG. 2B depicts a cross-sectional view of a streamer.

FIG. 3 depicts a close-up view of the embodiment shown in FIG. 2A.

FIG. 4 depicts a side-view of an embodiment of a closed apparatus thatis not attached to a streamer.

FIG. 5 depicts a side-view of an embodiment of an opened apparatus thatis not attached to a streamer.

FIG. 5A depicts an alternative embodiment of the apparatus.

FIG. 6 is an embodiment of a process using the apparatus in a cleaningoperation.

DETAILED DESCRIPTION

This specification includes references to “one embodiment” or “anembodiment.” The appearances of the phrases “in one embodiment” or “inan embodiment” do not necessarily refer to the same embodiment.Particular features, structures, or characteristics may be combined inany suitable manner consistent with this disclosure.

Various devices, units, circuits, or other components may be describedor claimed as “configured to”, “usable to”, or “operable to” perform atask or tasks. In such contexts, “configured to”, “usable to” and“operable to” is each used to connote structure by indicating that thedevices/units/circuits/components include structure that performs thetask or tasks during operation. As such, thedevice/unit/circuit/component can be said to be configured to, usableto, or usable to perform the task even when the specifieddevice/unit/circuit/component is not currently operational (e.g., is noton or in operation). The devices/units/circuits/components used with the“configured to”, “usable to”, or “operable to” language includehardware—for example, circuits, memory storing program instructionsexecutable to implement the operation, etc. Reciting that adevice/unit/circuit/component is “configured to”, “usable to”, or“operable to” perform one or more tasks is expressly intended not toinvoke 35 U.S.C. § 112(f), for that device/unit/circuit/component.

FIG. 1 shows an exemplary marine geophysical survey system as it istypically used in acquiring geophysical data for a survey. Survey vessel14 may move along the surface of body of water 11, such as a lake or theocean. The marine geophysical survey is intended to detect and recordgeophysical signals (e.g., seismic, electromagnetic, etc.) reflectedand/or refracted from the Earth's subsurface. Survey vessel 14 includessource actuation, data recording and navigation equipment, showngenerally at 12 and referred to for convenience as a “recording system.”Survey vessel 14, or a different vessel (not shown), may be configuredto tow, via source cable 24, one or more geophysical energy sources 23,or arrays of such sources (not shown) in body of water 11. Survey vessel14 or the different vessel may tow an array of streamers 10 throughwater 11. In some embodiments, the array of streamers 10 may extendbehind the survey vessel 14 or the different vessel for severalkilometers or more. At least one of streamers 10 typically includes aplurality of sensors 25 and/or a plurality of streamer positioningdevices 40. Sensors 25 may include hydrophones, geophones, electrodes,magnetometers or any other sensing device used to detect energyoriginating from geophysical energy source 23. At least one of streamers10 may include a plurality of connectors 26 and/or other relatedequipment (e.g., sensors, streamer positioning devices, birds, notseparately shown) along the lengths. In some embodiments, connectors 26may be configured to connect or interconnect various sections and/orsegments of streamer 10. In some cases, lead-in cables (not separatelyshown) are used at the front end of the towed streamer array to connectthe array to the survey vessel 14. Lead-in cables may generally includemultiplexed data transmission lines. Some lead-in cables may includeelectro-optic components.

During one embodiment of survey operation, relevant equipment (not shownseparately) in recording system 12 causes geophysical energy source 23to actuate at selected times. When actuated, geophysical energy source23 may produce geophysical energy 19 that emanates generally outwardlyfrom geophysical energy source 23. Geophysical energy 19 may traveldownwardly, through water 11, and may pass, at least in part, throughwater bottom 20 into the formations (not separately shown). Geophysicalenergy 19 may be at least partially reflected or refracted from one ormore impedance boundaries below water bottom 20, and may travel upwardlywhereupon it may be detected by sensors 25. Structure of the formations,among other properties of the Earth's subsurface, may be inferred bytravel time of geophysical energy 19 and by characteristics of thedetected geophysical energy such as its amplitude and phase.

Streamer positioning devices 40 may impart forces to streamer 10 inselected directions. Such streamer positioning devices may include oneor more rotatable control surfaces that, when moved to a selected rotaryorientation with respect to the direction of movement through the water,create a hydrodynamic lift in a selected direction to urge streamer 10in a selected direction. Such selected direction may be lateral (i.e.,perpendicular to the towing direction) or vertical (i.e., depth) withrespect to the array of streamer 10.

The quantity of streamers, sensors, streamer positioning devices, orconnectors shown in FIG. 1 is only for purposes of illustration and isnot a limitation on the number of each device that may be used in anyparticular embodiment. The broken lines in the array of streamers 10indicate that this figure is not necessarily drawn to scale. As shown inFIG. 1, apparatus 50 may be attached around an exterior surface of onestreamer 10. In other embodiments, apparatus 50 may be attached aroundsource cable 24, the lead-in cables, or any other towed geophysicalequipment that has a generally tubular structure.

FIG. 2A is an embodiment of apparatus 50 that may be attached aroundouter surface 15 of streamer 10. FIG. 2A is depicted from theperspective of survey vessel 14 from which apparatus 50 may be operated.As depicted, apparatus 50 may be operable from onboard survey vessel 14(or, more typically, another vessel (not shown)) in body of water 11.Streamer 10 is a generally tubular structure, and a cross-sectional viewof streamer 10 is shown in FIG. 2B. As shown in the cross-sectional viewof FIG. 2B, streamer 10 has outer surface 15. FIG. 2A shows streamer 10having longitudinal axis 59.

Apparatus 50 may include housing 30, having generally a cylindricaltubular structure in some embodiments. Housing 30 is configured tomovably couple to and around outer surface 15 of streamer 10. Housing 30may have an opening 45A at the proximal end of housing 30 and anotheropening 45B at the distal end. Streamer 10 may extend along longitudinalaxis 59 through openings 45A and 45B. In this particular embodimentillustrated in FIG. 2A, opening 45A of housing 30 may be attached orotherwise secured to one end of scraper 27.

Scraper 27 may be a metal scraper generally usable during geophysicalsurvey operations to remove debris from geophysical equipment. In theembodiment illustrated in FIG. 2A, scraper 27 may be in a closedconfiguration forming a generally tubular structure through whichstreamer 10 may extend along longitudinal axis 59. Scraper 27 maymovably attached to and around outer surface 15 of streamer 10. In someembodiments, scraper 27 may be clamped around outer surface 15 ofstreamer 10. In certain embodiments, scraper 27 may include polyurethanescraper blades that are configured to remove debris from outer surface15 of streamer 10 while remaining gentle to outer surface 15. In oneparticular embodiment, scraper 27 is made from stainless steel.

Scraper 27 may include handle (e.g., shaft) 41. One end of handle 41 maybe attached to scraper 27 generally at a portion 27A of scraper 27. Theother end of handle 41 may be onboard vessel 14 (or another vessel (notshown)). Handle 41 may be configured to control motion of scraper 27along longitudinal axis 59 of streamer 10. Handle 41 may be operable tocontrol motion of scraper 27 from onboard survey vessel 14 (or anothervessel (not shown)). In some embodiments, scraper 27 may be pulled alonglongitudinal axis 59 of streamer 10 by way of handle 41. As scraper 27is being pulled, scraper 27 may be moving or being displaced relative tostreamer 10. As a result, debris along outer surface 15 of streamer 10may be removed. In some embodiments, handle 41 may be manually operatedby crew onboard survey vessel 14. In other embodiments, handle 41 may beoperated by crew onboard of another vessel (not shown). In otherembodiments, handle 41 may be mechanically or electrically operated.

As housing 30 may be attached to scraper 27 in this embodiment, handle41 may control motion of both scraper 27 and housing 30. In oneembodiment, control of handle 41 may cause scraper 27 to move or bedisplaced along streamer 10. As scraper 27 may be coupled to apparatus50 by way of housing 30, apparatus 50 may in turn be moved or displaced.Other than scraper 27 and handle 41, any device that may connect tohousing 30 and/or control motion of housing 30 along streamer 10 wouldbe suitable.

Outer surface 15 may include a generally cylindrical structure which mayhave the same longitudinal axis 59 as streamer 10. Streamer 10 mayextend through the tubular structure of housing 30 such that housing 30may move along longitudinal axis 59 of streamer 10. Apparatus 50 mayalso include a plurality of scraping members 60. In this embodimentillustrated in FIG. 2A, scraping members 60 may be connected to housing30 by fasteners 13.

In some embodiments, scraping members 60 may include individual scrapingmembers 60A, 60B, and 60C (hereinafter “60A-60C”). Scraping members 60may be configured to extend away from housing member 30 alonglongitudinal axis 59. In some embodiments, some or all of scrapingmembers 60 may be generally finger-shaped. In other embodiments,scraping members 60 may be of a different shape such as a trapezoidshape and other shapes. Individual scraping members 60A-60C may havedifferent shapes with one another. In the embodiment illustrated in FIG.2A, individual scraping members 60A-60C may be of finger-shaped. In someembodiments, the distal ends of individual scraping members 60A-60C mayhave a generally flat edge. In other embodiments, scraping members 60may have non-uniform shapes. In the embodiment shown, individualscraping members 60A and 60B have different lengths, though they mayhave similar or identical lengths in other embodiments.

Each of individual scraping members 60A-60C may include a separateproximal end that is configured to couple to housing 30 at opening 45B.In these embodiments, the proximal end of each of individual scrapingmembers 60A-60C may be separately coupled to housing 30 at opening 45B.In some embodiments, scraping members 60 may include a proximal endcommon to (shared by) at least some of the individual scraping members.In one such embodiment, the common proximal end may be configured toattach to housing 30 at opening 45B. In such embodiments, individualscraping members may extend away from the common proximal end.

At least some of scraping members 60 such as individual scraping members60A-60C may be flexible or bendable. In some embodiments, individualscraping members 60A-60C may each be configured to generally conform toat least a portion of a contour of surface 15 of streamer 10. In some ofthese embodiments, the contour of surface 15 of streamer 10 may beirregular at least at some locations on streamer 10. In one embodiment,scraping members 60 may form a generally tubular structure with anopening on each end. The tubular structure, particularly the portiontoward the distal end of the tubular structure, may expand or contractas diameter of outer surface 15 may vary along the entire length ofstreamer 10. In some embodiments, scraping members 60 such as individualscraping members 60A-60C may, after expansion or contraction of thetubular structure, return to an unstressed state (not expanded orcontracted state) and retain their original shapes prior to theexpansion or contraction.

In this embodiment illustrated in FIG. 2A, as housing 30 may move alonglongitudinal axis 59, apparatus 50 that includes housing 30 attached toscraping members 60 may also move along the same axis. Distal ends ofscraping members 60 may be configured to generally curve toward streamer10 so that as apparatus 50 moves along longitudinal axis 59, scrapingmembers 60 clean and/or scrape outer surface 15 of streamer 10.

In some embodiments, as apparatus 50 may move along longitudinal axis59, scraping members 60 may clean streamer 10 by removing debris fromouter surface 15. In one embodiment, one or more individual scrapingmember of scraping members 60 is a flexible, finger-shaped structure. Insome embodiments, the flexible, finger-shaped structure is made from athermoplastic material such as polyurethane. A proximal end of each offlexible, finger-shaped structures may be attached to housing 30. Eachof the flexible, finger-shaped structures extends from the respectiveproximal end outwardly from housing 30, along the longitudinal axis 59.The respective distal end of each of the flexible, finger-shapedstructures may be free-moving, and in some embodiments, may have acurvature toward outer surface 15. In one embodiment, the flexible,finger-shaped structures may form a generally tubular structure with anopening. Streamer 10 may extend through the opening. In this embodiment,the distal end of the tubular structure may be generally cooperativelyengaged with and around outer surface 15 such that debris may be removedfrom outer surface 15 as the flexible, finger-shaped structures move andexert pressure around outer surface 15 along the length of streamer 10.The tubular structure, particularly the portion toward the distal end ofthe tubular structure, may expand or contract as diameter of outersurface 15 may vary. In some embodiments, the distal end of the tubularstructure, when not coupled to any geophysical equipment, has a diametersmaller than the diameter of outer surface 15. In some embodiments, someof the flexible, finger-shaped structures may have different lengths.

In some embodiments, some of the flexible, finger-shaped structures mayadditionally include a portion on the distal end that is made of ceramicor another material (such as metal, alloy, and other generally rigidmaterials) that is different from the material of the flexible,finger-shaped structures. In these embodiments, the distal end made ofceramic or other materials may be configured to exert additionalpressure to and around surface 15 of streamer 10 which may furtherincrease efficiency of debris removal.

As discussed above, streamer 10 may include in various locationsadditional equipment such as sensors, streamer positioning devices,birds, connectors, and other equipment. As such, streamer 10 may not beuniform in diameter along the entire length. Some locations of streamer10 may have diameters that are different than other locations. Forexample, at a location where streamer 10 includes a streamer positioningdevice, the diameter of that particular location may be larger than alocation without any additional equipment. Furthermore, as the streameris towed, the towing force exerted on streamer 10 may cause certainparts of streamer 10 to compress and/or flatten. At locations wherestreamer 10 is compressed and/or flattened, the resulting diameters maybe smaller than those unaffected portions of streamer 10. In someembodiments, the flattened or compressed section of streamer 10 maygenerally be of an oval shape, and at least one diameter of theflattened or compressed section may be smaller than that of theunaffected section of streamer 10.

As apparatus 50 may move from one location of streamer 10 to anotherlocation, where the two locations have different diameters, scrapingmembers 60 may expand or contract in response to changes in diameter ofthese locations. As such, scraping members 60 may remain generallyengaged with and around outer surface 15. In one embodiment, scrapingmembers 60 may form a generally tubular structure around outer surface15. The generally tubular structure may generally maintain contact withouter surface 15. Such structure may generally conform to and aroundouter surface 15. The generally tubular structure may exert pressure onand around outer surface 15 along the length of streamer 10 and removedebris from outer surface 15. Outer surface 15 may include at least oneor more of the following along the length of streamer 10: a sensor, astreamer positioning device, a bird, and a connector.

Turing to FIG. 3 which is an embodiment of apparatus 50 attached tostreamer 10. As discussed earlier, apparatus 50 may include scrapingmembers 60 and housing 30. In the embodiment shown in FIG. 3, housing 30may be attached to scraper 27 (the curved lines of scraper 27 indicatethat the illustration shows a truncated scraper 27 and the remainingportions of scraper 27 are not shown). Portion 27A of scraper 27generally indicates a portion of scraper 27 that may be attached tohandle 41 (shown in FIG. 2A). Scraping members 60 may include aplurality of individual scraping members such as individual scrapingmembers 60A-60C. In some embodiments, individual scraping member 60A maybe made from a thermoplastic material. Such material may include a typeof medium density, hard plastic material such as polyurethane and othersimilar materials. In one embodiment, a molded or extruded polymer maybe used. Yet in other embodiments, scraping members 60 may include aninternal skeleton whose exterior may be coated by a plastic or polymericmaterial. A variety of materials may be used for the construction of theinternal skeleton such as a composite material, metal, alloys andothers. The plastic or polymer coating may include a molded or extrudedpolymer or other similar materials.

One end, such as a proximal end, of individual scraping member 60A maybe fixed within housing 30. In some other embodiments, scraping member60A may share a common proximal end with other scraping members and thecommon proximal end may be configured to be fixed within housing 30. Inthe particular embodiment illustrated in FIG. 3, a proximal end scrapingmember 60A may be fixed within housing 30 by fasteners 13. The distal orscraping end of individual scraping member 60A, which is outside ofhousing 30, extends away from housing 30. Distal or scraping end ofindividual scraping member 60A may exert pressure on and around at leasta portion of outer surface 15. Individual scraping member 60A mayadditionally include portion 82 on the distal or scraping end. Portion82 may be made of a different material than that of scraping members 60.For example, portion 82 may be made of a ceramic material, a metal, analloy, or other generally rigid material. In other embodiments, portion82 may be removable and/or insertable relative to individual scrapingmember 60A.

In some embodiments, the distal or scraping end of individual scrapingmember 60A may curve toward and be engaged with and around outer surface15. Individual scraping member 60A may be flexible and curved towardouter surface 15 such that the distal or scraping end generally conformsto and around outer surface 15. Furthermore, individual scraping member60A may be configured so that the distal or scraping end exertsgenerally constant pressure on at least a portion of outer surface 15along a length of streamer 10. In other embodiments, the pressure mayvary in accordance with changes in outer surface 15, but still besufficient to scrape effectively regardless of such variations. In someembodiments, outer surface 15 may additionally include, in locationsalong the length of streamer 10, one or more streamer positioning device(not separately shown).

In FIG. 3, scraping members 60 may also include individual scrapingmember 60B that neighbors individual scraping member 60A. In someembodiments, individual scraping member 60B may be identical instructure to scraping member 60A. Yet in some other embodiments,individual scraping member 60B may have a dimension other than that ofscraping member 60A. For example, individual scraping member 60B may beshorter than scraping member 60A. Individual scraping member 60B mayhave a larger width than scraping member 60A. Individual scraping member60B may have a different curvature than scraping member 60A. In someembodiments, portions of individual scraping members 60A and 60Bpartially or completely overlap. In these and other embodiments,individual scraping members 60A and 60B are together configured toscrape an area on outer surface 15.

In FIG. 3, scraping members 60 may also include individual scrapingmember 60C. Individual scraping member 60C may be identical to one ofindividual scraping members 60A and 60B. Individual scraping member 60Cmay have dimensions different than either individual scraping member 60Aor 60B. Individual scraping member 60C may partially or completelyoverlap with one or more of the neighboring individual scraping members(not separately shown). As shown, distal or scraping end 86 ofindividual scraping member 60C may curve toward outer surface 15. Outersurface 15 may have irregular contours along the entire length ofstreamer 10. Distal or scraping end 86 of individual scraping member 60Cmay be configured to generally maintain contact with outer surface 15.Distal or scraping end 86 of the individual scraping member 60C may besimilarly configured to exert pressure on outer surface 15 such thatdebris may be removed (i.e., scraped) from outer surface 15. Pluralityof scraping members 60 may include additional individual scrapingmembers (not separately identified in FIG. 3); these additionalindividual scraping members may have a similar dimension and/orconfiguration with any of scraping member 60A, 60B, or 60C.

Scraping members 60 may generally conform to and around outer surface 15of streamer 10 when the diameter of streamer 10 is variable (e.g., notuniform) along the entire length. In some embodiments, scraping members60 may expand when a diameter of streamer 10 increases from one sectionto another. For example, at a section of streamer 10 where streamer 10includes a sensor, the diameter of streamer 10 at that section may belarger than another section of streamer 10 without the sensor. In thatparticular embodiment, scraping members 60 may expand such that scrapingmembers 60 generally remain in contact with and exert pressure on andaround outer surface 15 such that outer surface 15 is scraped byscraping members 60. In yet some other embodiments, a section (e.g., asegment) of streamer 10 may flatten or compress. In some cases, towingforce exerted on streamer 10 may stretch streamer 10 in the towingdirection and thus cause certain sections of streamer 10 to flatten orcompress. In a flattened or compressed section of streamer 10, thediameter of that particular section may be smaller than a section ofstreamer 10 unaffected and/or unchanged by the towing force. In someembodiments, the flattened or compressed section may generally be of anoval shape, and at least one diameter of the flattened or compressedsection may be smaller than that of the unaffected section. In theseembodiments, scraping members 60 may contract in response to thedecrease in diameter as the section of streamer flattens or compresses.

FIGS. 4 and 5 show a stand-alone apparatus 50 not attached to astreamer, wherein apparatus 50 is erected with housing 30 as a base.FIG. 4 depicts apparatus 50 in a closed configuration, wherein FIG. 5depicts apparatus 50 in an open configuration. As shown in FIG. 5,housing 30 may include three separate portions, 30A, 30B, and 30C. Inthe open configuration shown in FIG. 5, a truncated depiction of scraper27 is shown to be open showing three connected portions. Housingportions 30A, 30B, and 30C may each be configured to attach torespective scraping members 61, 62, and 63, each of which may furthercomprise various individual scraping members such as individual scrapingmembers 60A, 60B, and 60C. In one embodiment, each of housing portions30A, 30B, and 30C may include a plurality of sockets (e.g., 8), and eachsocket may be attached to an individual scraping member such as scrapingmember 60A, 60B, 60C, or others. In this particular embodiment, scrapingmembers 60 would include a total of 24 individual scraping members. Inthis particular embodiment, each of scraping members 61, 62, and 63would include 8 individual scraping members.

In other embodiments, some individual scraping members such as scrapingmember 60A, 60B, 60C, and/or others may share a common proximal end, andsuch common proximal end may be secured to one socket of 30A, 30B, or30C. In this particular embodiment, instead of each individual scrapingmember being attached to an individual socket of housing portions 30A,30B, and 30C, a common proximal end may be configured to attach to thecorresponding socket or other relevant components of housing portions30A, 30B, or 30C. Individual scraping members such as scraping member60A, 60B, 60C, and/or others may extend from the common proximal end andalong the length of streamer 10. In this particular embodiment, scrapingmembers 61, 62, 63, and/or others would include the common proximal endfrom which individual scraping members extend.

In some embodiments, each of 61, 62, and 63 may include a plurality ofindividual scraping members such as scraping member 60A, 60B and 60C. Insome embodiments, scraping members 61, 62, and 63 may contain the samequantity and configuration of identical individual scraping members. Inother embodiments, at least two of scraping members 61, 62, and 63 maycontain individual scraping members that differ in quantity,arrangement, and/or configuration. In yet other embodiments, some ofscraping members 61, 62, and 63 may include a common proximal endconfigured to attach to housing portions 30A, 30B, or 30C, andindividual scraping members extending from the common proximal end alongstreamer 10; whereas others may include individual scraping members thatare configured to attach to sockets or other relevant components ofhousing portions 30A, 30B, or 30C.

In the embodiment of FIG. 5, side 32 of housing portion 30B may bemovably connected to side 33 of housing portion 30C, whereas side 31 of30B may be movably connected to side 36 of 30A. Side 34 of housingportion 30C may be configured to be connected to side 35 of housingportion 30A upon which housing 30 closes (three sides of scraper 27likewise closes). Sides 31, 32, 33, 34, 35, and 36 of housing portions30A, 30B, or 30C may be arranged in various configurations.

In the embodiment illustrated in FIG. 4, all sides of housing portions30A, 30B, and 30C are connected with one another, and housing 30 orapparatus 50 closes (housing portion 30B is not shown in FIG. 4). FIG. 4also shows a truncated scraper 27 in a closed configuration. In thisdepiction, housing 30 and scraping members 60 may form an opening or anannular space shown as 65 through which streamer 10 may extend alonglongitudinal axis 59. In one embodiment, the diameter of annular space65 near the scraping or distal end of scraping members 60 isapproximately 40 mm. In this embodiment, the diameter of annular space65, when idle (not coupled to any geophysical equipment), is smallerthan the diameter of streamer 10 (e.g., 10 cm or less). In thisembodiment, when streamer 10 extends along longitudinal axis 59 throughannular space 65 of apparatus 50, scraping members 60 may expand so thatstreamer 10 may extend through annular space 65. Scraping members 60 mayexpand and generally conform to the generally cylindrical structure ofstreamer 10. Scraping members 60 may exert pressure around thecylindrical structure and generally maintain contact with and aroundouter surface 15 of streamer 10.

In a particular embodiment, a streamer 10 may include two sections(segments), a first section of streamer 10 may include one or more ofthe following equipment: a streamer, a source cable, a lead-in cable, orany combination thereof. In certain embodiments, the first section ofstreamer 10 may include one or more of the following equipment: asensor, a streamer positioning device, a bird, or a connector. The firstsection of streamer 10 may include debris on and around surface 15 suchas algae and/or barnacles. Apparatus 50 may firstly move alonglongitudinal axis 59 at the first section of streamer 10. Handle 41 thatis attached to scraper 27 (by way of housing 30 that may be attached toscraper 27) may be operable to move apparatus 50. As apparatus 50 movesalong the first section of streamer 10, apparatus 50 including scrapingmembers 60 may be operable to exert pressure (e.g., scrape) aroundscrape surface 15 of the first section of streamer 10. Apparatus 50 mayremove debris from surface 15 of the first section of streamer 10through the pressure exerted.

In some embodiments, apparatus 50 may subsequently be moved to a secondsection of streamer 10. Handle 41 may be operable to control themovement apparatus 50 from the first section to the second section. Inthis embodiment, the second section of streamer 10 may have a diametersmaller than that of the first section. As apparatus 50 may subsequentlybe moved to the second section, scraping members 60 including the curveddistal or scraping ends contract such that scraping members 60 generallyremain in contact with and around surface 15 of the second section ofstreamer 10. Contracted apparatus 50 including scraping members 60 mayexert pressure around surface 15 of the second section of streamer 10.Although the second section of streamer 10 has a diameter smaller thanthat of the first section in this particular embodiment, the contractingof apparatus 50 including scraping members 60 allows scraping members 60to generally engaged with and around surface 15 of the second section.As such, apparatus 50 including scraping members 60 may exert pressurearound surface 15 of the section second and remove debris thereon. Inthese embodiments, apparatus 50 including scraping members 60 may expandor contract in response to varying diameters of streamer 10 through itslength. Apparatus 50 may generally remain engaged with and aroundsurface 15 of streamer 10 as apparatus 50 may be moved or displacedalong the length of streamer 10.

FIG. 5A shows an alternative embodiment of individual scraping member60A. In this embodiment, one or more individual scraping member such asscraping member 60A may additionally include a spring assembly 88.Individual scraping member 60A may be attached to connecting apparatus58 by hinge pivot 68A. Connecting apparatus 58 may be bolted to housing30A or attached to housing 30A by other means. A truncated depiction ofscraper 27 is shown and housing 30A may be connected to scraper 27 inthis embodiment. Connecting apparatus 58 may be made of materials suchas metal, alloy, composite material, or other generally rigid materials.Spring assembly 88 may include spring tension member 48 which may beconnected to individual scraping member 60A via hinge pivot 68B. In thisembodiment, pressure exerted by spring tension member 48 may be adjustedby adjusting screw 38. Individual scraping member 60A including springassembly 88 may be configured to conform to a varying shape and/ordiameter of streamer 10. In other alternative embodiments, instead ofspring assembly 88, a hydraulic assembly, a pneumatic assembly, aservomotor assembly, a combination of such assemblies, or other similarassemblies may be attached to individual scraping member 60A and/orother individual scraping members. Yet in other embodiments, springassembly 88 may additionally include a hydraulic component, a pneumaticcomponent, a servomotor component, a combination of such components, orother similar components.

FIG. 6 is a flow diagram illustrating one exemplary embodiment of amethod 900 for cleaning a geophysical equipment (e.g., a streamer) usingapparatus 50. The method shown in FIG. 6 may be used in conjunction withany of the devices, elements, or components disclosed herein, amongother devices. In various embodiments, some of the method elements shownmay be performed concurrently, in a different order than shown, or maybe omitted. Additional method elements may also be performed as desired.Flow begins at block 910.

At block 910, a survey vessel towing geophysical equipment such as acable in a body of water, wherein a towing force is exerted on thecable. Flow proceeds to block 920.

At block 920, in response to the towing force, a section or a segment ofthe cable flattening or compressing, while another section of the cableremains unaffected. The flattened or compressed section may have asmaller diameter than that of the unaffected section. In someembodiments, the flattened or compressed section may generally be of anoval shape, and at least one diameter of the flattened or compressedsection may be smaller than that of the unaffected section. Flowproceeds to block 930.

As block 930, at least one scraping member of an apparatus exertingpressure on the unaffected section of the cable. The apparatus may beattached around the cable and may have a movable housing and the atleast one scraping member attached to the housing. The at least onescraping member exerting pressure on and cleaning this particularsection of the cable. Flow proceeds to block 940.

At block 940, the apparatus moving to the flattened or compressedsection of the cable. In some embodiments, the apparatus may be attachedto a scraper (e.g., a metal scraper used in debris removal ofgeophysical equipment), and a handle attached to the scraper may controlthe motion of both the apparatus and the scraper. In these embodiments,one end of the handle may be onboard of a survey vessel or anothervessel, and another end of the handle may be attached to the scraper.Crew onboard of the survey vessel or another vessel may control themotion of both the apparatus and the scraper by way of the handle. Asthe apparatus may be moving to the flattened or compressed section ofthe cable, the at least one scraping member contracting and exertingpressure on the flattened or compressed section of the cable. The atleast one scraping member cleaning the flattened or compressed sectionof the cable. Flow proceeds to block 950.

At block 950, the apparatus moving to an unaffected section of thecable. This unaffected section may be the section discussed at block 930or another section of the cable. This unaffected section of the cablemay have a diameter larger than the flattened or compressed section. Inresponse to the moving, the apparatus expanding and exerting pressure onthe unaffected section of the cable. The at least one scraping membercleaning this particular section of the cable. Flow ends at block 950.

Towing geophysical equipment (such as streamers) and other equipmentthrough the water may cause noise in the recorded data. Towing may causevibrations in the geophysical equipment (such as streamers) due toturbulent flow past the surface of the geophysical equipment. Thevibrations may lead to additional noise picked up by the sensors on thegeophysical equipment. The vibration noise may affect pressure sensorssuch as the hydrophones and/or particle motion sensors such as thegeophones. An apparatus in accordance with this disclosure may be usedto reduce the drag due to turbulence on the geophysical equipment andother towed equipment thereby reducing the vibration noise, improvingthe quality of the survey results. Improvements of the quality of thesurvey results may aid in yielding information relating to the geologicstructure and properties of the subterranean formations in the areabeing surveyed. Knowledge of the subsurface structure of the Earth maybe useful for locating and extracting hydrocarbon deposits including oiland natural gas.

An apparatus in accordance with this disclosure may be used to improvethe efficiency and safety of maintenance of geophysical equipment (suchas streamers). The apparatus may also be used to reduce drag resistancein geophysical equipment during towing. Reduction in drag resistance mayincrease towing capacity including the capacity to tow more and longerstreamers for surveying. Additional towing capacity may result inextended operational life, increased productivity and reduced operationcost. Further, reduced drag leads to reduced fuel costs for towing andresults in savings in the overall operation cost of a survey.

Although specific embodiments have been described above, theseembodiments are not intended to limit the scope of the presentdisclosure, even where only a single embodiment is described withrespect to a particular feature. Examples of features provided in thedisclosure are intended to be illustrative rather than restrictiveunless stated otherwise. The above description is intended to cover suchalternatives, modifications, and equivalents as would be apparent to aperson skilled in the art having the benefit of this disclosure.

The scope of the present disclosure includes any feature or combinationof features disclosed herein (either explicitly or implicitly), or anygeneralization thereof, whether or not it mitigates any or all of theproblems addressed herein. Accordingly, new claims may be formulatedduring prosecution of this application (or an application claimingpriority thereto) to any such combination of features. In particular,with reference to the appended claims, features from dependent claimsmay be combined with those of the independent claims and features fromrespective independent claims may be combined in any appropriate mannerand not merely in the specific combinations enumerated in the appendedclaims.

What is claimed is:
 1. A method for cleaning geophysical equipment,comprising: towing the geophysical equipment behind a survey vessel; andperforming a movement of a housing along a longitudinal axis of thegeophysical equipment to remove debris, wherein portions of the housingdefine first and second openings through which sections of thegeophysical equipment travel during the movement, wherein the firstopening has a fixed size, wherein the housing includes a plurality ofnondeforming scraping members each having respective distal ends thatdefine the second opening, and wherein, during the movement, theplurality of scraping members are configured to move to adjust a size ofthe second opening to conform to sections of the geophysical equipmenthaving different cross-sectional areas.
 2. The method of claim 1,wherein the geophysical equipment comprises at least one type ofequipment selected from the group consisting of: a streamer, a sourcecable, and a lead-in cable.
 3. The method of claim 1, wherein a firstsection of the geophysical equipment has a diameter smaller than that ofa second section, and wherein the movement causes the housing to moveover the second section prior to the first section.
 4. The method ofclaim 3, further comprising, in response to a towing force exerted onthe geophysical equipment, the first section of the geophysicalequipment compressing or flattening to have the smaller diameter.
 5. Themethod of claim 3, wherein the first section of the geophysicalequipment includes at least one type of equipment selected from a groupconsisting of: a sensor, a streamer positioning device, a bird, and aconnector.
 6. The method of claim 1, wherein the plurality of scrapingmembers are finger-shaped.
 7. A method for cleaning geophysicalequipment, comprising: towing the geophysical equipment behind one ormore survey vessels, wherein the geophysical equipment comprises astreamer, and wherein the streamer comprises a plurality of sensors;receiving geophysical data via the sensors; and moving a housing along alongitudinal axis of the geophysical equipment, wherein, during themoving, a scraping member of the housing scrapes an outer surface of thegeophysical equipment to remove debris, wherein the scraping member isdisposed at least partially outside of the housing and includes aplurality of members, wherein, during the moving, the plurality ofmembers flexibly conform to sections of the geophysical equipment havingdifferent cross-sectional areas, and wherein a particular one of theplurality of members includes a mechanical assembly that is configuredto conform the particular member to the sections of the geophysicalequipment.
 8. The method of claim 1, wherein a particular one of theplurality of scraping members includes a mechanical assembly that isconfigured to conform the particular scraping member to the sections ofthe geophysical equipment.
 9. The method of claim 1, wherein at leastone of the plurality of scraping members includes a portion on a distalend that is made of a material different than a material of a flexibleportion of the at least one scraping member.
 10. The method of claim 1,wherein at least one of the plurality of scraping members includes aportion that curves towards the longitudinal axis of the geophysicalequipment from a position at least partially disposed parallel to thelongitudinal axis of the geophysical equipment.
 11. The method of claim1, wherein a first one of the plurality of scraping members comprises adifferent length than a second one of the plurality of scraping members.12. A method for cleaning geophysical equipment, comprising: towing thegeophysical equipment behind a survey vessel; and performing a movementof a housing along a longitudinal axis of the geophysical equipment toremove debris, wherein portions of the housing define first and secondopenings through which sections of the geophysical equipment travelduring the movement, wherein the first opening has a fixed size, whereinthe housing includes a plurality of scraping members each havingrespective distal ends that define the second opening, and wherein theplurality of scraping members are configured to move to adjust a size ofthe second opening to conform to sections of the geophysical equipmenthaving different cross-sectional areas, and wherein at least one of theplurality of scraping members includes a portion that curves towards thelongitudinal axis of the geophysical equipment from a position at leastpartially disposed parallel to the longitudinal axis of the geophysicalequipment.
 13. The method of claim 12, wherein an amount that theportion curves toward the longitudinal axis of the geophysical equipmentdefines the size of the second opening.
 14. The method of claim 12,wherein an amount that the portion curves toward the longitudinal axisof the geophysical equipment is based on a size of a section of thegeophysical equipment that the portion scrapes during the movement.